Coil mounting



July 27, 1948. R, T, THOMPSON 2,445,979

COIL MOUNTING Filed Dec. 31, 1945 FIG.5

ROBERT 'l'. THOMPSON INVENToR.

HIS AGE/VT' Patented July 27, 1948 COIL MOUNTING Robert T. Thompson, Oak Park, Ill., assignor to Zenith Radio Corporation, a corporation of Illinois Application December 31, 1943, Serial No. 516,361

s claims. 1

This invention relates to the construction of an impedance or transformer and mounting therefor. Y

In radio circuits having fixed transmission channels, for example, the intermediate frequency channel of a superheterodyne receiver, it is desirable to have the transformers for such channels of simple inexpensive construction allowing ease of manufacture and allowing ease of adjustment in operation of such radio circuits.

A radio transformer requires two windings interlinked with magnetic flux. An .impedance element requires but one winding. In the manufacture of radio equipment which requires both transformers and impedance elements, it is desirable to make a winding for use either as an impedance element or for use as one element of a transformer. That is, the winding should be interchangeable for use either as an impedance element or as one element of a transformer.

An object of the present invention is to provide a new and improved transformer construction.

A further object of the present invention is to provide a new and improved winding for use either as one element of a, transformer or as one impedance element.

The features of the present invention which are believed to be novel are set forth with partlcularity Vin the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing in which:

Figure 1 is a. sectional view of apparatus embodying the present invention, taken substantially on line I-I of Fig. 2 with certain elements disengaged;

Fig. 2 is a plan view of a radio frequency transformer construction embodying this invention with the top plate of a shield can removed;

Fig. 3 is a, view in perspective, partly in seci tion, of the radio frequency transformer construction shown in Fig. 2;

Fig. 4 shows one of the elements embodying this invention employed as an impedance element, and

Fig. 5 shows another construction embodying the present invention.

The windings IIl and II comprising the windings of an adjustable radio frequency transformer are wound respectively on tubular members I2 and Il of insulating material. Tubular member I2 has an internally tapped screw threaded portion I4 for adjustably holding a cooperating screw-threaded powdered iron core member I6 and for receiving a cooperating threaded portion Il of member I3. Tubular member I3 has, in addition to the screw-threaded projection Il, a threaded internal Aportion I9 for adjustably holding a powdered iron threaded core member 2I The members I2 and I3 are joined to on'e another and mounted on a supporting member 24 by passing the threaded projection Il of member I3 through an aperture 25 in member 24 and screwing such projection I'I into the cooperating threaded portion I4 of member I2.

. In a preferred form of the invention, the coils I0 and II are permanently wound on their respective members I2 and I3 and the spacing between such coils may be altered either by providing supporting members 24 of various thicknesses or by providing shims or spacers 21 between the supporting member 24 and shoulder 29 of member I3.

The magnetic coupling between coils I0 and II is not only varied by varying their physical spacing but is varied also by movi-ng either one of the powdered iron core members I6 or 2l in their respective supporting members I2 and I3. This particular feature allows ease of adjustment of coupling and tuning when the windings I0 and II, respectively, form elements of a tuned primary winding and tuned secondary winding in an intermediate frequency transformer in a superheterodyne radio receiver.

The supporting member 24 preferably comprises a fiat metal or insulating sheet supported in a rectangular or square metal shielding box 30`with the sheet dimensions such that its length as shown in Fig. 2 corresponds to that of a diagonal of the rectangular box 3D. WhereI the two coils are intended to be magnetically coupled, of course, the sheet 24 is of insulating material.

Where the supporting member 24 is of metal, the Winding I0 is electrostatically shielded from the winding I I, and the two windings maybe used as independent impedances not coupled with each other.

Ir the arrangement shown in Fig. 2, the supporting member 24 carrying adjustable transformer windings I0 and II is easily inserted into or removed from the rectangularly shaped shielding -box 30 within which it is held by cooperation of the opposite edges of supporting member 24 in diagonally opposite corners of box 30.

Holes 34 and 35 in box 30 aligned with the axis of the members I6 and 2I allow passage of an adjusting tool, for example, a screwdriver, arranged to enter grooves 36 and 3l whereby the position of members I6 and 2| may be adjusted or varied by manipulating such screwdriver.

The leads of coils I and i| are connected respectively to binding posts 39, 40 and 4|, 42 insulated from each other and mounted on the supporting member 24. Such an arrangement allows the composite transformer to be removed from its supporting shield can 30 by removing the lid 44 and lifting the supporting member 24 out of such box. If desired, lid 44 may be permanently or semipermanently fastened in place on box 30 by soldering or the like, it being understood that adjustments may be made on the connected transformer by passing a screwdriver or the like through apertures-34 or 35 in box 30 and turning either one of the core members I6 Fig. 4 shows one of the elements of the transformer shown in Figs. 1 to 3 used as an impedance device. Corresponding parts in the different figures have identical reference numerals. In Fig. 4, the cylindrical coil holder I3 having coil Ii wound thereon is fastened to the chassis of a radio receiver or base member 32 by screwing.

the screw-threaded projection I1 into ya cooperating tapped screw threaded opening 33 in base member 32.

The inductance of coil I I in Fig. 4 is altered by adjusting the position of powdered iron core member 2| in its cooperating screw-threaded portion i9 in member I3. The coil may form one element 'of a tuned circuit whose tuning may be effected by varying the position of powdered iron core member 2|. Also in one embodiment of my invention, coil II may serve as a choke coil in which case the member 2| is preferably positi-oned as far as possible within the hollow portion of coil I.

In Fig. 5, the coil holder |3.having mounted thereon coil lIl is fastened to fastening member 24 by passing the threaded projection l'l through the aperture 26 in supporting member 24 and threading a nut 45 on threaded projection I1. The leads yof coil II are connected to binding vposts or terminals 4I and 42 which are insulated electrically from each other and which extend to the opposite side of member 24 so that a fixed condenser 43 of conventional shape and const-ruction may have its Iopposite leads connected, as for example, by solder, to such terminals 4| and 42. The position of the powdered iron core member 2| threaded in coil holder I3 may be adjusted by inserting a screwdriver through aperture 35 in metal can 30 and then turning such vcore member with the screwdriver to adjust the resonant frequency of the resulting tuned circuit,

In Fig. 5, the coil II and shunt connected condenser 48 form an adjustable tuned circuit which may be employed in a lradio circuit as a Wave trap or, for example, as a tuned input or output circuit for an electron discharge device.

In the preferred embodiment of my invention, the core members i6 and 2| are screw-threadedly mounted in their insulating supporting members I2 and I3, respectively. It is understood, however, that other means may be used to hold the core members adjustably in their respective sup- .4 tallic material held in diagonally opposite corners of Ia box or shield can.

While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects. and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

1. In a mounting for a transformer, a metal box, a. rst winding, a winding holder having a screw-threaded projection and having a tapped inner portion, an adjustable core member in said coil holder, a supporting sheet having anyaperture through which said projection extends, a second winding, a second winding holder having a tapped portion arranged to receive said screwthreaded projection with said supporting sheet clamped between the two coil holders, an 'adjustable core member on said second coil holder, whereby said first winding, second winding and said supporting sheet may be moved as a. unit apart from said box, said metal box having oppositely disposed corners receiving snugly the edges of said supporting sheet.

2. In a mounting for a transformer, a box, a first winding, a winding holder having a screwthreaded projection, a supporting sheet having an aperture for said projection, a second winding. a. second winding holder having a tapped portion arranged to receive said second screw-threaded projection with said support sheet clamped between the two coil holders, whereby said first winding, second winding and supporting sheet may be movedas a unit apart from said box, said box having oppositely disposed corners receiving snugly the edges of said supporting sheet.

- 3. In combination, a shield box, a coil, a coil support having a screw-threaded projection, a supporting sheet having an aperture for said projection, a second coil, a coil support for said second coil having a tapped inner portion for engagement with said projection with said supporting sheet between the two coil supports, an adjustable core member mounted in said tapped inner portion, terminals for said coils mounted on said supporting sheet, whereby said coil, second coils and supporting sheet may be moved as a unit 'apart from said shield box, said shield box having oppositely disposed corners receiving snugly said supporting sheet.

4. In a mounting for a transformer, a first winding, a first winding holder having a projection and having a tapped inner portion, an adprojection with said supporting sheet clamped between the two coil supports, an adjustable core member mounted in said tapped inner portion, and terminals for said coils mounted on said supporting sheet.

6. A shielded impedance comprising a shield box of rectangular cross section having oppositely disposed corners, a rectangular supportingsheet fitted snugly in said box between said corners and having an aperture intermediate said corners, a coil form of insulating material, a coil wound on said form, and means for fastening one end of said form in said aperture, said means including screw threads in said one end of said form.

'1. A shielded transformer comprising a shield box of rectangular cross section having oppositely disposed corners, a rectangular supporting sheet ofy insulating material iltted snugly in said box between said corners and having an aperture intermediate said corners, a pair of coll forms ol' insulating material, a coil wound on each of said forms, and means 4for fastening said forms through said aperture with said coils in coaxial alignment, said means-including screw threads in adjacent ends of said forms.

8. A shielded transformer comprising a shield box of rectangular cross section having oppositely disposed-corners, a rectangular supporting sheet of insulating material ntted snugly in said box between said corners, and having an aper- 25 ture intermediate said corners, a pair of hollow cylindrical coil forms o1' insulating material, a

coil wound on each of said forms coaxially therewith, a powdered iron core adjustably supported within each of said forms, and means for fastening said forms through said aperture with said coils and forms in coaxial alignment, said means including screw threads in adjacent ends of said forms.

ROBMT T. THOMPSON.

REFERENCES CITED `The following references are of record in the ille of this patent:

UNITED STATES 'PATENTS 

